I think this is definitely moving in the right direction, but more so with the legs; they are more shapely and look more accurate by way of anatomy. I think looking at some anatomy books and really studying the curves of the muscles and joints of the body will help you. The arms are nice but too smooth and...rubbery....looking...for lack of a better word.
xp Sorry, not trying to be brutal...
*I would red-line for you but I lack the proper equipment ><*
But anyways...here is a site that may help with different anatomy (if you are interested...(I take no credit for it, of course, a friend just sent me a link to it)
sweatdrop I have been doing a few studies from it and I really love it. Hope it helps...(though I haven't looked for hand studies but they may have hands too)
http://www.posemaniacs.com/index.php